Method of applying curved leg elastics using pucks with curved surfaces

ABSTRACT

A method of applying curved leg elastics to absorbent garments involves stretching and wrapping a pair of elastic ribbons about a first curved surface of a pair of pucks. A portion of each of the elastic ribbons is simultaneously folded onto a second surface of each of the pucks. The pucks are attached to a rotating device that rotates the pucks into alignment with a substrate. As the pucks are rotated toward the substrate, the pucks are also oscillated individually toward the substrate. Once the second surfaces of the pucks are aligned parallel to the substrate, the substrate is bonded to the second surface portion of each of the elastic ribbons in their stretched positions on the pucks, thereby forming finished seams. The resulting absorbent garments have gasket-like leg openings with improved comfort and aesthetic appeal.

FIELD OF THE INVENTION

This invention is directed to a method of producing fully encircling,curved leg elastics. The method involves placing a pair of elasticribbons on a pair of semi-curved pucks, each puck having a curvedsurface adjacent a preferably curved top surface, and subsequentlyapplying the elastic ribbons to a substrate.

BACKGROUND OF THE INVENTION

Pant-like absorbent garments, such as adult incontinence wear, as wellas infant and children's diapers, swim wear and training pants,typically include a pair of leg openings having an elastic portionaround each leg opening. The elastic portions are intended to fit snuglyaround a wearer's legs to prevent leakage from the garment.

Various technologies are known for applying leg elastics to sucharticles. For example, one technology involves bonding a continuous loopto a substrate. However, producing a supply of continuous loops ofelastic strands is more costly and cumbersome than providing a supply ofa continuous length of elastic ribbons.

Articles which incorporate conventional elasticized margins andconventional barrier flap configurations at their leg openings have,however, exhibited various shortcomings. For example, it has beendifficult to avoid pressure-induced marking of the wearer's skin anddifficult to maintain the desired gasketing of the leg openings when thearticles are being worn. Even when the leg openings are fitted with anelastomeric material or otherwise elasticized, it has been difficult tomaintain contact between the leg opening and the wearer's body for aneffective containment of urine and feces. As a result, there has been acontinued need for improved containment structures at the leg regions ofthe absorbent articles.

There is a need or desire for a process for making comfortable,gasket-like leg elastics that are aesthetically pleasing and can beapplied in a high-speed application.

SUMMARY OF THE INVENTION

The present invention is directed to a method of applying curved legelastics to pant-like absorbent garments using semi-curved pucks. Theresult is a comfortable, flexible, aesthetically pleasing leg opening.Furthermore, the resulting leg opening is form-fitting and acts like agasket.

Apparatus that can be used for carrying out the invention includes apair of rotating devices, with at least one corresponding semi-curvedpuck attached to a periphery of each of the rotating devices. Each puckhas a first curved surface adjacent a preferably curved second surface.The apparatus also includes a pair of cutting devices and a pair ofbonding devices.

In carrying out the invention, each elastic ribbon of a pair of elasticribbons is guided onto one of the pucks on one of the rotating devices,deflected to conform to the first curved surface of the puck, and cutoff with a cutting device after conforming to a length of the firstcurved surface of the puck. The elastic ribbons are guided onto thepucks such that a portion of each of the elastic ribbons overhangs theedge of the first curved surface of the corresponding puck. Tension inthe elastic ribbon causes the overhanging portion to fold over onto theadjacent second surface of the puck around which the elastic ribbon isstretched. Alternatively, the elastic ribbons may already be in discretelengths prior to carrying out the method of the invention. A vacuumand/or friction surface is used to hold the elastic ribbons in place onthe pucks. The rotating devices continue to advance the pucks toward thebonding devices. While the rotating devices rotate, the pucks areradially displaced from a position at which the elastic ribbons areguided onto the pucks to a position wherein the second surfaces of thepucks are substantially parallel to a substrate. Once the pucks aresubstantially parallel to and in contact with the substrate, theportions of the elastic ribbons folded onto the second surfaces of thepucks are bonded to the substrate. The substrate is typically a liner oran outer cover of the absorbent garment.

The method of the invention can be used in high-speed applications,namely applications running at linear speeds of 600 feet per minute orgreater. More than one corresponding pair of semi-curved pucks can belocated on the peripheries of the rotating devices to enable a moreexpedient process. The rotating devices can be adjusted to change pitchor machine direction spacing between adjacent pucks from the point ofapplication of the elastic ribbons to the pucks to the point where theelastic ribbons are transferred and bonded to the substrate.

The substrate may be stretchable or extensible, thereby providing greatflexibility and enabling the elastic ribbons to be applied at lowtension. Furthermore, stretchability and/or extensibility of thesubstrate provide for a larger leg fit range.

The resulting product is an absorbent garment having a comfortable,aesthetically pleasing, finished look about the leg openings. Thismethod can also be used to apply curved standing leg cuffs and/or curvedleak guard flaps.

With the foregoing in mind, it is a feature and advantage of theinvention to provide a method of applying curved leg elastics to anabsorbent garment.

It is another feature and advantage of the invention to provide a methodof applying leg elastics to an absorbent garment resulting ingasket-like leg openings.

It is yet another feature and advantage of the invention to provide amethod of applying leg elastics to an absorbent garment resulting inform-fitting leg openings.

It is a further feature and advantage of the invention to provide amethod of applying leg elastics to an absorbent garment resulting incomfortable and aesthetically pleasing leg openings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of an absorbent garment;

FIG. 2 is a top view of apparatus, including two rotating devices eachhaving six pucks, used to produce curved leg elastics;

FIG. 3 is a front view of the apparatus in FIG. 2, showing four of thepucks on each of the rotating devices;

FIG. 4 is a side view of the apparatus of FIGS. 2 and 3, showing six ofthe pucks in six different positions;

FIG. 5 is a perspective view of one of the pucks of the apparatus shownin FIGS. 3 and 4, wherein the puck is in a position prior to a bondingposition;

FIG. 6 is a perspective view of the puck in FIG. 5, wherein the puck hasbeen rotated to be placed in a suitable bonding position;

FIG. 7 is a top view of a substrate, showing a pair of curved legelastics bonded to the substrate;

FIG. 8 is a front view of an absorbent garment showing how the legelastics are bonded to the substrate;

FIG. 9 is a front view of an absorbent garment showing leg elasticmembers with rolled edges; and

FIG. 10 is a plan view of the absorbent garment of FIG. 1 in a partiallydisassembled, stretched flat state, and showing the surface of thearticle that faces the wearer when the article is worn, and withportions cut away to show the underlying features.

DEFINITIONS

Within the context of this specification, each term or phrase below willinclude the following meaning or meanings. “Bonded” refers to thejoining, adhering, connecting, attaching, or the like, of two elements.Two elements will be considered to be bonded together when they arebonded directly to one another or indirectly to one another, such aswhen each is directly bonded to intermediate elements. “Curved” refersto an opening, band, flap, surface, or edge, at least a portion of whichis curved, i.e. has a radius of curvature and an arc covering at least30°. Preferably, the opening, band, flap, surface, or edge is curvedover at least 90°, more preferably at least 180°.

“Disposable” refers to articles which are designed to be discarded aftera limited use rather than being laundered or otherwise restored forreuse.

“Elastic,” “elasticized” and “elasticity” mean that property of amaterial or composite by virtue of which it tends to recover itsoriginal size and shape after removal of a force causing a deformation.

“Elastomeric” refers to a material or composite which can be elongatedby at least 25 percent of its relaxed length and which will recover,upon release of the applied force, at least 10 percent of itselongation. It is generally preferred that the elastomeric material orcomposite be capable of being elongated by at least 100 percent, morepreferably by at least 300 percent, of its relaxed length and recover,upon release of an applied force, at least 50 percent of its elongation.

“Extensible” refers to a material capable of being extended or protrudedin length or breadth.

“Film” refers to a thermoplastic film made using a film extrusion and/orfoaming process, such as a cast film or blown film extrusion process.The term includes apertured films, slit films, and other porous filmswhich constitute liquid transfer films, as well as films which do nottransfer liquid. The term also includes film-like materials that existas open-celled foams.

“Force” includes a physical influence exerted by one body on anotherwhich produces acceleration of bodies that are free to move anddeformation of bodies that are not free to move.

“Hydrophilic” describes fibers or the surfaces of fibers which arewetted by the aqueous liquids in contact with the fibers. The degree ofwetting of the materials can, in turn, be described in terms of thecontact angles and the surface tensions of the liquids and materialsinvolved. Equipment and techniques suitable for measuring thewettability of particular fiber materials or blends of fiber materialscan be provided by a Cahn SFA-222 Surface Force Analyzer System, or asubstantially equivalent system. When measured with this system, fibershaving contact angles less than 90° are designated “wettable” orhydrophilic, while fibers having contact angles greater than 90° aredesignated “nonwettable” or hydrophobic.

“Layer” when used in the singular can have the dual meaning of a singleelement or a plurality of elements.

“Leg elastic” includes elastic bands, strands, ribbons, filaments,filament bunches and the like, which are adjacent to a garment openingthat receives a wearer's leg.

“Liquid impermeable,” when used in describing a layer or multi-layerlaminate, means that a liquid, such as urine, will not pass through thelayer or laminate, under ordinary use conditions, in a directiongenerally perpendicular to the plane of the layer or laminate at thepoint of liquid contact. Liquid, or urine, may spread or be transportedparallel to the plane of the liquid impermeable layer or laminate, butthis is not considered to be within the meaning of “liquid impermeable”when used herein.

“Liquid-permeable material” or “liquid water-permeable material” refersto a material present in one or more layers, such as a film, nonwovenfabric, or open-celled foam,. which is porous, and which is waterpermeable due to the flow of water and other aqueous liquids through thepores. The pores in the film or foam, or spaces between fibers orfilaments in a nonwoven web, are large enough and frequent enough topermit leakage and flow of liquid water through the material.

“Longitudinal” and “transverse” have their customary meaning, asindicated by the longitudinal and transverse axes depicted in FIG. 10.The longitudinal axis lies in the plane of the article and is generallyparallel to a vertical plane that bisects a standing wearer into leftand right body halves when the article is worn. The transverse axis liesin the plane of the article generally perpendicular to the longitudinalaxis. The article as illustrated is longer in the longitudinal directionthan in the transverse direction.

“Meltblown fibers” means fibers formed by extruding a moltenthermoplastic material through a plurality of fine, usually circular,die capillaries as molten threads or filaments into converging highvelocity heated gas (e.g., air) streams which attenuate the filaments ofmolten thermoplastic material to reduce their diameter, which may be tomicrofiber diameter. Thereafter, the meltblown fibers are carried by thehigh velocity gas stream and are deposited on a collecting surface toform a web of randomly dispersed meltblown fibers. Such a process isdisclosed for example, in U.S. Pat. No. 3,849,241 to Butin et al.Meltblown fibers are microfibers which may be continuous ordiscontinuous, are generally smaller than about 0.6 denier, and aregenerally self bonding when deposited onto a collecting surface.Meltblown fibers used in the present invention are preferablysubstantially continuous in length.

“Member” when used in the singular can have the dual meaning of a singleelement or a plurality of elements.

“Nonwoven” and “nonwoven web” refer to materials and webs of materialwhich are formed without the aid of a textile weaving or knittingprocess.

“Operatively attached,” in reference to the attachment of an elasticmember to another element, means that the elastic member when attachedto or connected to the element, or treated with heat or chemicals, bystretching, or the like, gives the element elastic properties; and withreference to the attachment of a non-elastic member to another element,means that the member and element can be attached in any suitable mannerthat permits or allows them to perform the intended or describedfunction of the composite. The joining, attaching, connecting or thelike can be either directly, such as joining either member directly toan element, or can be indirectly by means of another member disposedbetween the first member and the first element, or can be such that afirst member is mechanically trapped by adjacent bond points in a firstelement such that the first member causes the composite to exhibitcharacteristics of the first member.

“Polymers” include, but are not limited to, homopolymers, copolymers,such as, for example, block, graft, random and alternating copolymers,terpolymers, etc. and blends and modifications thereof. Furthermore,unless otherwise specifically limited, the term “polymer” shall includeall possible geometrical configurations of the material. Theseconfigurations include, but are not limited to isotactic, syndiotacticand atactic symmetries.

“Spunbonded fibers” refers to small diameter fibers which are formed byextruding molten thermoplastic material as filaments from a plurality offine capillaries of a spinnerette having a circular or otherconfiguration, with the diameter of the extruded filaments then beingrapidly reduced as by, for example, in U.S. Pat. No. 4,340,563 to Appelet al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S. Pat. No.3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and 3,341,394 toKinney, U.S. Pat. No. 3,502,763 to Hartmann, U.S. Pat. No. 3,502,538 toPetersen, and U.S. Pat. No. 3,542,615 to Dobo et al., each of which isincorporated herein in its entirety by reference. Spunbond fibers arequenched and generally not tacky when they are deposited onto acollecting surface. Spunbond fibers are generally continuous and oftenhave average deniers larger than about 0.3, more particularly, betweenabout 0.6 and 10.

“Stretchable” means that a material can be stretched, without breaking,by at least 50% (to 150% of its initial (unstretched) length) in atleast one direction, suitably by at least 100% (to 200% of its initiallength), desirably by at least 150% (to at least 250% of its initiallength).

“Surface” includes any layer, film, woven, nonwoven, laminate,composite, or the like, whether pervious or impervious to air, gas,and/or liquids.

“Tension” includes a uniaxial force tending to cause the extension of abody or the balancing force within that body resisting the extension.

“Thermoplastic” describes a material that softens when exposed to heatand which substantially returns to a nonsoftened condition when cooledto room temperature.

These terms may be defined with additional language in the remainingportions of the specification.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The present invention is directed to a method of applying curved legelastics to pant-like absorbent garments. Curved leg elastics, inaccordance with the invention, are leg elastics that follow a curvedcontour of a leg opening. The present invention results in curved legelastics having an unbonded elastic portion spanning an entire length ofthe leg elastics and a bonded elastic portion also spanning an entirelength of the leg elastics. The unbonded portion and the bonded portionare both part of a solitar unit, or ribbon, of elastic. The bondedportion is a portion of the elastic ribbon that is bonded to asubstrate. The unbonded portion can extend away from the bonded portionat an angle, or can lie juxtaposed to the bonded portion via a foldalong the length of the elastic ribbon. The unbonded portion has greaterfreedom to respond to internal tension when the garment is in a relaxedstate than the bonded portion, attributable to the fact that the bondedportion is bonded to the substrate in a stretched state, thereby causingthe bonded portion to be restrained in movement by the substrate. Theresulting disproportionate freedom of movement along the length of theelastic ribbon causes a curvature of the elastic ribbon. In addition tothe curvature caused by the disproportionate freedom of movement, thebonded portion is bonded to the substrate along a periphery of a curvedcut-out in the substrate. The curved shape of the bonded portionincreases the curvature of the leg elastics.

The principles of the present invention can be incorporated into anysuitable disposable absorbent article. Examples of such suitablearticles include diapers, training pants, feminine hygiene products,incontinence products, other personal care or health care garments, orthe like. As used herein, the term “incontinence products” includesabsorbent underwear for children, absorbent garments for children oryoung adults with special needs such as autistic children or others withbladder/bowel control problems as a result of physical disabilities, aswell as absorbent garments for incontinent older adults. For ease ofexplanation, the description hereafter will be in terms of a child'straining pant. Furthermore, the principles of the present invention canbe used to apply leg elastics, crotch elastics, as well as leak guardflaps or leg cuffs, to the leg openings of pant-like absorbent garments.For ease of explanation, the description hereafter will be in terms ofleg elastics.

Referring to FIG. 1, a disposable absorbent article, such as a trainingpant 20, is illustrated in a fastened condition. Leg elastics 10 areused around leg openings 12 of the training pant 20 to create a gasketand to reduce or prevent leakage. The term “gasket” refers to a devicethat is used to block fluid leakage around the leg openings, between thegarment and legs of a wearer. A main chassis 14 defines the leg openings12 and a waist opening 13. When the leg elastics 10 are curved, as inthe present invention, the leg elastics 10 are more form-fitting thanstraight edge leg elastics. The term “straight edge leg elastics” refersto typical leg elastics that are attached to a substrate in a straightline. With curved leg elastics, the leg openings 12 are gathered withlow tension, since the leg openings 12 do not have to overcome forcesfrom a main chassis 14 as straight edge leg elastics must overcome. Thelow tension and form-fit results in an absorbent garment 20 withincreased comfort. Additionally, the curved leg elastics 10 have afinished seam 16 where attached to the main chassis 14, resulting in anaesthetically pleasing appearance.

One example of apparatus 3 for carrying out the invention is showngenerally in FIGS. 2, 3 and 4. The apparatus 3 includes a pair ofrotating devices 22 with at least one pair of corresponding semi-curvedpucks 24 attached to a periphery of the corresponding rotating devices22. Six pairs of semi-curved pucks 24 are shown in FIG. 2. Four pairs ofpucks are shown in FIG. 3. The other two pairs of pucks are not shown inFIG. 3 for reasons of clarity. The term “semi-curved” refers to a puckhaving at least one curved surface which extends partially around thepuck, but less than all the way around the puck. The semi-curved pucks24 of the present invention preferably have curved contours on at leasttwo adjacent surfaces. The curved surfaces may vary in terms of degreesof curvature along their lengths, with optimal curvature of a firstsurface 26 conforming to curvature about a wearer's leg, and optimalcurvature of a second surface 28 such that the second surface 28 forms arolling action when the puck 24 is in position to transfer and bond anelastic ribbon 10 to a substrate 40. Preferably, the first curvedsurface 26 extends about 90-270° around the puck, more preferably about135-225°. Similarly, the leg elastics 10 are preferably curved about thefull circumference of the leg openings 12, but may alternatively onlypartially encircle the leg openings 12, thereby resulting in curved legelastics that are not fully encircling.

A semi-curved puck 24 used in the invention is shown separately in FIGS.5 and 6. As mentioned above, the puck 24 has a first curved surface 26,a back wall 27, and a second surface 28, preferably having a curvaturecorresponding to the radius of the rotating device 22 (FIGS. 2-4). Thefirst curved surface 26 is preferably curved more at one end 21 than atthe other end 25, as shown in FIGS. 5 and 6. The puck can have a backwall 27 of any shape, including flat, as shown in FIGS. 5 and 6, curvedor even a concave curvature following the shape of the first curvedsurface 26. FIGS. 5 and 6 also show a tensioned elastic ribbon 10wrapped about the first curved surface 26 of the puck 24, as explainedbelow.

The rotating devices 22 each rotate about an axis 23 in a directioncomplementary to the machine direction movement of the substrate 40. Themachine direction is indicated by the arrow 47 in FIGS. 2 and 4. Themachine direction in FIG. 3 is into the paper. Guide rolls 36 and acutting device 34 are located in close proximity to each of the rotatingdevices 22, but not necessarily in close proximity to one another (FIG.4). As shown in FIG. 4, the cutting devices 34 may also be used todeflect the web path of the elastic ribbons 10 onto the pucks 24. Abonding device 32, such as an ultrasonic bonder, is also located inclose proximity to each of the rotating devices 22, and may be locatedbelow the substrate 40, as shown in FIGS. 3 and 4. The pucks 24 caneither rotate onto the substrate 40 with sufficient pressure for thebonding process or, alternatively, the bonding devices 32 can exertforce upward to carry out the bonding process.

In carrying out the invention, as shown in FIG. 2, the elastic ribbons10 are guided through the cutting devices 34 and onto the pucks 24 asthe rotating devices 22 rotate. As the elastic ribbons 10 are guidedthrough the cutting devices 34, the cutting devices are used to deflectthe elastic ribbons 10 to follow the contours of the first curvedsurfaces 26 of the pucks 24. As the pucks 24 are rotated past thecutting devices 34, the cutting devices 34 displace the elastic ribbons10 causing them to conform to the first curved surface 26 of the pucks24 and subsequently cut the elastic ribbons 10 into discrete pieces orsegments. Examples of suitable cutting devices 34 include mechanicalpinch type cut-off knives, shear type cut-off knives, and hot knives orother cutting means well known in the art. A vacuum within the pucks 24is used to hold the elastic ribbons 10 in place on the pucks 24.Alternatively or additionally, the pucks 24 can have a nonslip textureon at least part of the first curved surfaces 26 and on at least part ofthe adjacent second curved surfaces 28 to hold the elastic ribbons 10 inplace. The elastic ribbons 10 are guided onto the first curved surfaces26 of the pucks 24 such that a first portion 38 of the elastic ribbons10 is placed on the first curved surfaces 26 of the pucks 24 while asecond portion 39 of the elastic ribbons 10 overhangs the edge of thefirst curved surface 26. Tension in the elastic ribbons 10 and thecurvature of the first surface 26 cause the second portion 39 of theelastic ribbons 10 to fold onto the adjacent second curved surfaces 28of the pucks 24. The elastic ribbons 10 are preferably stretched to atleast 125%, more preferably at least 150%, of their initial(unstretched) length as they are wrapped about the first curved surface26 of the puck 24. The cutting device 34 is not necessarily directlymounted to the rotating device 22, but is mounted at least in closeproximity to the rotating device 22.

Once the elastic ribbons 10 have been cut into discrete lengths, thepucks 24 are rotated (approximately 45-135 degrees) from the positionshown in FIG. 5 to the position shown in FIG. 6. The puck 24 in FIG. 5is in roughly the same orientation as the pucks 24 indicated by thearrow 61 in FIGS. 2 and 3. Similarly, the puck 24 in FIG. 6 is inroughly the same orientation as the pucks 24 indicated by the arrow 64in FIGS. 2 and 3. The pucks 24 indicated by the arrow 62 in FIGS. 2 and3 shows how the puck 24 has rotated from a position 61 wherein the firstcurved surface 26 of the puck 24 is substantially parallel to thesubstrate 40 in a position at which the elastic ribbons 10 are appliedto the pucks 24; to an intermediate position 62; and further progressionto a position 63; prior to reaching a position 64 wherein the adjacentsecond curved surface 28 of the puck 24 is substantially parallel to thesubstrate 40. The second curved surface 28 of the puck 24 in position 61need not be perpendicular to the substrate 40, but may be in a range ofapproximately 45-135 degrees from parallel to the substrate 40.

Through the rotation of the rotating devices 22, the pucks 24 areradially displaced to increase the pitch from the elastic-applicationposition 61 to the substrate bonding position 64. Meanwhile, therotating devices 22 continue to rotate the pucks 24 toward the substrate40. By the time the pucks 24 have been rotated to the substrate 40, thesecond curved surfaces 28 of the pucks 24 are in substantially parallelalignment with the substrate 40.

The first portions 38 of the elastic ribbons 10 are then bonded to thesubstrate 40 in a machine direction. The substrate 40 is typically aliner 42 or an outer cover 44 of the absorbent garment 20 (FIG. 1). Asshown in FIGS. 2 and 7, the substrate 40 preferably includescorresponding curved cut-outs along parallel edges 46 of the substrate40. The term “curved cut-out” refers to any cut-out having a curvededge, which may include a single material that is cut to form a cut-outor a plurality of materials that are bonded together to define a cut-outshape. The curved cut-outs are preferably roughly the same contour asthe first curved surface 26 of the semi-curved pucks 24, but the curvedcut-outs have an area slightly smaller than an area of the second curvedsurface 28 of each of the pucks 24. Prior to bonding the elastic ribbons10 to the substrate 40, the curved cut-outs are aligned within aperimeter of the second curved surface 28 of the pucks 24. As a result,the second portions 39 of each of the elastic ribbons 10 are bonded tothe substrate 40 along an edge adjacent each of the curved cut-outs. Thefirst portions 38 of the elastic ribbons 10 project upward from thesubstrate 40 and serve as gaskets during later use of the garment 20, asexplained below.

The substrate 40 can be a continuous length, as shown in FIG. 2, inwhich case the substrate 40 is cut into individual pieces for eachgarment 20 subsequent to the application of the elastic ribbons 10.Alternatively, the substrate 40 can be fed through the apparatus 3 inthe form of individual pieces for each garment 20, similar to the shapeof the substrate 40 in FIG. 7. The substrate 40 is preferablystretchable and/or extensible, thereby providing great flexibility,enabling the elastic ribbons 10 to be applied at low tension, andenabling a wide leg fit range.

As the elastic ribbons 10 are bonded to the substrate 40, the rotatingdevices 22 and the pucks 24 continue to rotate. As the rotating devices22 advance the pucks 24 from position 64 to position 65 to position 66(FIG. 2), the pucks 24 are returning to their initial alignment of thesecond curved surface 28 being substantially perpendicular to thesubstrate 40, or in a range of approximately 45-135 degrees fromparallel to the substrate 40 as previously mentioned.

By the time the pucks 24 reach position 66 (FIG. 2), the first curvedsurfaces 26 are substantially parallel to the substrate 40 and in aposition ready for the next elastic ribbons 10 to be guided onto thecontour of the first curved surfaces 26 of the pucks 24. And so theprocess continues.

Each of the pucks 24 is actuated to oscillate individually usingstationary spiral cam tracks and multiple cam followers positionedaround a pivot point of an arm supporting each of the pucks 24. Therotating device 22 can be a high efficiency interface roll, as disclosedin U.S. Pat. No. 5,556,504. Other examples of suitable rotating devicesare disclosed in U.S. Pat. Nos. 5,716,478 and 5,759,340. Additionally,cam boxes, gear racks, bevel gears, and hinge points with plows areother examples of suitable rotating devices 22.

FIG. 8 is a front view of an absorbent garment 20 with a pair of curvedleg elastics 10 bonded to the substrate 40, in this case, the outercover 44. FIG. 9 is a front view of an absorbent garment 20 showing thecurved leg elastics 10 with rolled edges 58. The rolled edges 58 providegreater strength and reinforcement around the leg openings 12, inaddition to an even more finished look. The rolled edges 58 can containa strand of elastic to provide an even more effective gasket. Aresulting seam 16 (see also FIGS. 1 and 8) joining the leg elastics 10and the substrate 40 has a finished appearance since edges of thesubstrate 40 and the second portion 39 of the leg elastics 10 are bothhidden from view on one side of the seam 16.

The second portions 39 of the elastic ribbons 10 can be bonded to thesubstrate 40 by ultrasonic bonding, as mentioned, or a variety of othertechniques including adhesive bonding, thermal bonding, stitch bondingor other conventional techniques. Suitable adhesives include sprayadhesives, hot melt adhesives, self-adhering elastomeric materials andthe like. Each suitable bonding technique is strong enough to separatethe elastic ribbons 10 from the vacuum in the pucks 24, oralternatively, from the nonslip texture of the pucks 24. As a furtheralternative, the vacuum itself can be released, thereby releasing theelastic ribbons 10 from the pucks 24.

Once the elastic ribbons 10 have been bonded to the substrate 40, edges50 and 51 can be joined to edges 52 and 53, respectively, shown in FIG.7, to form the garments 20 shown in FIGS. 1 and 8. Once the garment 20is formed, the first portions 38 of the elastic ribbons 10 can projectupward from the garment surface. During use, the first portions 38 ofthe elastic ribbons 10 firmly engage the wearer's skin, thereby servingas gaskets to reduce or prevent leakage through the openings of thegarment 20.

The method of the invention can be used in high-speed applications,namely applications running at linear speeds of 600 feet per minute orgreater. More than one semi-curved puck 24 can be located on theperiphery of the rotating device 22 to enable a more expedient process.Preferably, at least three of the pucks 24 are located on the peripheryof the rotating device 22. More preferably, six to eight of the pucks 24are located on the periphery of the rotating device 22. The rotatingdevice 22 can be adjusted to change pitch, velocity and/or machinedirection spacing between application of the elastic ribbons 10 from thepucks 24 to the substrate 40.

Referring to FIG. 10, the absorbent garment 20 of FIG. 1 is shown in apartially disassembled, stretched flat state, showing a surface whichfaces the wearer when the garment is worn. In addition to defining theleg openings 12 and the waist opening 13 (FIG. 1), the absorbent chassis14 also defines a pair of transversely opposed side edges 136 and a pairof longitudinally opposed waist edges, which are designated front waistedge 138 and back waist edge 139. The chassis 14 also includes asomewhat rectangular composite structure 133, a pair of transverselyopposed front side panels 134, and a pair of transversely opposed backside panels 234. The composite structure 133 and side panels 134 and 234may be integrally formed, as shown in FIG. 7, or may include two or moreseparate elements, as shown in FIGS. 1 and 10.

The illustrated composite structure 133 includes an outer cover 44, abody side liner 42 which is connected to the outer cover in a superposedrelation, and an absorbent assembly 144 which is located between theouter cover 44 and the body side liner 42. The rectangular compositestructure 133 has opposite linear end edges 145 that form portions ofthe front and back waist edges 138 and 139, and opposite linear, orcurvilinear, side edges 147 that form portions of the side edges 136 ofthe absorbent chassis 14. Leg openings 12 (FIG. 1) are generally definedby portions of the transversely opposed side edges 136. For reference,arrows 48 and 49 depicting the orientation of the longitudinal axis andthe transverse axis, respectively, of the training pant 20 areillustrated in FIG. 10.

The liquid permeable body side liner 42 is illustrated as overlying theouter cover 44 and absorbent assembly 144 (FIG. 10), and may but neednot have the same dimensions as the outer cover 44. The body side liner42 is desirably compliant, soft feeling, and non-irritating to thechild's skin. Further, the body side liner 42 can be less hydrophilicthan the absorbent assembly 144, to present a relatively dry surface tothe wearer and permit liquid to readily penetrate through its thickness.

The absorbent assembly 144 (FIG. 10) is positioned between the outercover 44 and the body side liner 42, which components can be joinedtogether by any suitable means, such as adhesives, as is well known inthe art. The absorbent assembly 144 can be any structure which isgenerally compressible, conformable, non-irritating to the child's skin,and capable of absorbing and retaining liquids and certain body wastes.The absorbent assembly 144 can be manufactured in a wide variety ofsizes and shapes, and from a wide variety of liquid absorbent materialscommonly used in the art. For example, the absorbent assembly 144 cansuitably include a matrix of hydrophilic fibers, such as a web ofcellulosic fluff, mixed with particles of a high-absorbency materialcommonly known as superabsorbent material. In a particular embodiment,the absorbent assembly 144 includes a matrix of cellulosic fluff, suchas wood pulp fluff, and superabsorbent hydrogel-forming particles. Thewood pulp fluff can be exchanged with synthetic, polymeric, meltblownfibers or with a combination of meltblown fibers and natural fibers. Thesuperabsbrbent particles can be substantially homogeneously mixed withthe hydrophilic fibers or can be nonuniformly mixed. The fluff andsuperabsorbent particles can also be selectively placed into desiredzones of the absorbent assembly 144 to better contain and absorb bodyexudates. The concentration of the superabsorbent particles can alsovary through the thickness of the absorbent assembly 144. Alternatively,the absorbent assembly 144 can include a laminate of fibrous webs andsuperabsorbent material or other suitable means of maintaining asuperabsorbent material in a localized area.

Suitable superabsorbent materials can be selected from natural,synthetic, and modified natural polymers and materials. Thesuperabsorbent materials can be inorganic materials, such as silicagels, or organic compounds, such as crosslinked polymers. Suitablesuperabsorbent materials are available from various commercial vendors,such as Dow Chemical Company located in Midland, Michigan, U.S.A., andStockhausen GmbH & Co. KG, D-47805 Krefeld, Federal Republic of Germany.Typically, a superabsorbent material is capable of absorbing at leastabout 15 times its weight in water, and desirably is capable ofabsorbing more than about 25 times its weight in water.

In one embodiment, the absorbent assembly 144 is generally rectangularin shape, and includes a blend of wood pulp fluff and superabsorbentmaterial. One preferred type of fluff is identified with the tradedesignation CR1654, available from Kimberly-Clark Corporation, Neenah,Wis., U.S.A., and is a bleached, highly absorbent sulfate wood pulpcontaining primarily soft wood fibers. As a general rule, thesuperabsorbent material is present in the absorbent assembly 144 in anamount of from about 0 to about 90 weight percent based on total weightof the absorbent assembly. The absorbent assembly 144 suitably has adensity within the range of about 0.10 to about 0.35 grams per cubiccentimeter. The absorbent assembly 144 may or may not be wrapped orencompassed by a suitable tissue wrap that maintains the integrityand/or shape of the absorbent assembly.

The absorbent chassis 14 can also incorporate other materials that aredesigned primarily to receive, temporarily store, and/or transportliquid along the mutually facing surface with the absorbent assembly144, thereby maximizing the absorbent capacity of the absorbentassembly. One suitable material is referred to as a surge layer (notshown) and includes a material having a basis weight of about 50 gramsper square meter, and including a through-air-bonded-carded web of ahomogenous blend of 60 percent 3 denier bicomponent fiber including apolyester core/polyethylene sheath, commercially available from BASFCorporation, and 40 percent 6 denier polyester fiber, commerciallyavailable from Hoechst Celanese Corporation, in Portsmouth, Virginia,U.S.A.

A wide variety of elastic materials may be used for the leg elastics 10.As is well known to those skilled in the art, suitable elastic materialsinclude sheets, strands or ribbons of natural rubber, synthetic rubber,or thermoplastic elastomeric polymers. The elastic materials can bestretched and adhered to a substrate, adhered to a gathered substrate,or adhered to a substrate and then elasticized or shrunk, for examplewith the application of heat; such that elastic constrictive forces areimparted to the substrate. In one particular embodiment, for example,the leg elastics 10 include a plurality of dry-spun coalescedmultifilament spandex elastomeric threads sold under the trade nameLYCRA® and available from E.I. DuPont de Nemours and Company,Wilmington, Delaware, U.S.A.

Each of the leg elastics 10 preferably has a width of about 0.5 inch(1.27 cm) to about 5 inches (12.7 cm), more preferably about 1 inch(2.54 cm) to about 4 inches (10.16 cm), most preferably about 1.5 inches(3.81 cm) to about 2.5 inches (6.35 cm). Second portions 39 of the legelastics 10 preferably have a width of about 0.25 inch (0.635 cm) toabout 4 inches (10.16 cm), more preferably about 0.5 inch (1.27 cm) toabout 3 inches (7.62 cm), most preferably about 1 inch (2.54 cm) toabout 2 inches (5.08 cm). The length of the leg elastics 10 once cut bythe cutting device 34 should substantially cover a circumference of theleg opening 12. Depending on the garment size, the leg elastics 10 mayhave a length of at least about 4 inches, preferably at least about 8inches, more preferably at least about 12 inches. Of course, the lengthsare shorter if the leg elastics 10 are not intended to fully encircle awearer's legs. Furthermore, each of the leg elastics 10 preferably haselongation of 25-350%, more preferably about 30-260%, most preferablyabout 35-200%.

The substrate 40 is preferably the outer cover 44 and desirably includesa material that is substantially liquid impermeable, and can be elastic,stretchable or nonstretchable. The outer cover 44 can be a single layerof liquid impermeable material, but desirably includes a multi-layeredlaminate structure in which at least one of the layers is liquidimpermeable. For instance, the outer cover 44 can include a liquidpermeable outer layer and a liquid impermeable inner layer that aresuitably joined together, such as by a laminate adhesive (not shown).Suitable laminate adhesives, which can be applied continuously orintermittently as beads, a spray, parallel swirls, or the like, can beobtained from Findley Adhesives, Inc., of Wauwatosa, Wisconsin, U.S.A.,or from National Starch and Chemical Company, Bridgewater, New Jersey,U.S.A. The liquid permeable outer layer can be any suitable material anddesirably one that provides a generally cloth-like texture. One exampleof such a material is a 20 gsm (grams per square meter) spunbondpolypropylene nonwoven web. The outer layer may also be made of thosematerials of which liquid permeable bodyside liner 42 is made. While itis not a necessity for the outer layer to be liquid permeable, it isdesired that it provides a relatively clothlike texture to the wearer.

The inner layer of the outer cover 44 can be both liquid and vaporimpermeable, or can be liquid impermeable and vapor permeable. The innerlayer is desirably manufactured from a thin plastic film, although otherflexible liquid impermeable materials may also be used. The inner layer,or the liquid impermeable outer cover 44 when a single layer, preventswaste material from wetting articles, such as bedsheets and clothing, aswell as the wearer and caregiver. A suitable liquid impermeable film foruse as a liquid impermeable inner layer, or a single layer liquidimpermeable outer cover 44, is a 0.02 millimeter polyethylene filmcommercially available from Huntsman Packaging of Newport News,Virginia, U.S.A. If the outer cover 44 is a single layer of material, itcan be embossed and/or matte finished to provide a more cloth-likeappearance. As earlier mentioned, the liquid impermeable material canpermit vapors to escape from the interior of the disposable absorbentarticle, while still preventing liquids from passing through the outercover 44. A suitable “breathable” material is composed of a microporouspolymer film or a nonwoven fabric that has been coated or otherwisetreated to impart a desired level of liquid impermeability. A suitablemicroporous film is a PMP-1 film material commercially available fromMitsui Toatsu Chemicals, Inc., Tokyo, Japan, or an XKO-8044 polyolefinfilm commercially available from 3M Company, Minneapolis, Minnesota.

The bodyside liner 42 can be manufactured from a wide selection of webmaterials, such as synthetic fibers (for example, polyester orpolypropylene fibers), natural fibers (for example, wood or cottonfibers), a combination of natural and synthetic fibers, porous foams,reticulated foams, apertured plastic films, or the like. Various wovenand nonwoven fabrics can be used for the bodyside liner 42. For example,the bodyside liner can be composed of a meltblown or spunbonded web ofpolyolefin fibers. The bodyside liner can also be a bonded-carded webcomposed of natural and/or synthetic fibers. The bodyside liner can becomposed of a substantially hydrophobic material, and the hydrophobicmaterial can, optionally, be treated with a surfactant or otherwiseprocessed to impart a desired level of wettability and hydrophilicity.For example, the material can be surface treated with about 0.28 weightpercent of a surfactant commercially available from the Rohm and HaasCo. under the trade designation Triton X-102. The surfactant can beapplied by any conventional means, such as spraying, printing, brushcoating or the like. The surfactant can be applied to the entirebodyside liner 42 or can be selectively applied to particular sectionsof the bodyside liner, such as the medial section along the longitudinalcenterline.

A suitable liquid permeable bodyside liner 42 is a nonwoven bicomponentweb having a basis weight of about 27 gsm. The nonwoven bicomponent canbe a spunbond bicomponent web, or a bonded carded bicomponent web.Suitable bicomponent staple fibers include a polyethylene/polypropylenebicomponent fiber available from CHISSO Corporation, Osaka, Japan. Inthis particular bicomponent fiber, the polypropylene forms the core andthe polyethylene forms the sheath of the fiber. Other fiber orientationsare possible, such as multi-lobe, side-by-side, end-to-end, or the like.While the outer cover 44 and bodyside liner 42 can include elastomericmaterials, it can be desirable in some embodiments for the compositestructure to be generally inelastic, where the outer cover, the bodysideliner and the absorbent assembly include materials that are generallynot elastomeric.

As noted previously, the illustrated training pant 20 can have front andback side panels 134 and 234 disposed on each side of the absorbentchassis 14 (FIGS. 1 and 10). These transversely opposed front sidepanels 134 and transversely opposed back side panels 234 can bepermanently bonded to the composite structure 133 of the absorbentchassis 14 and are releasably attached to one another by a fasteningsystem 80 (FIG. 1). More particularly, as shown best in FIG. 10, thefront side panels 134 can be permanently bonded to and extendtransversely beyond the linear side edges 147 of the composite structure133 along attachment lines 69, and the back side panels 234 can bepermanently bonded to and extend transversely beyond the linear sideedges of the composite structure along attachment lines 69. The sidepanels 134 and 234 may be attached using attachment means known to thoseskilled in the art such as adhesive, thermal or ultrasonic bonding. Theside panels 134 and 234 can also be formed as a portion of a componentof the composite structure 133, such as the outer cover 44 or the bodyside liner 42.

Each of the side panels 134 and 234 can include one or more individual,distinct pieces of material. In particular embodiments, for example,each side panel 134 and 234 can include first and second side panelportions that are joined at a seam, with at least one of the portionsincluding an elastomeric material (not shown). Still alternatively, eachindividual side panel 134 and 234 can include a single piece of materialwhich is folded over upon itself along an intermediate fold line (notshown).

The side panels 134 and 234 desirably include an elastic materialcapable of stretching in a direction generally parallel to thetransverse axis 49 of the training pant 20. In particular embodiments,the front and back side panels 134 and 234 may each include an interiorportion 78 disposed between a distal edge 68 and a respective front orback center panel 135 or 235. In the illustrated embodiment in FIG. 10,the interior portions 78 are disposed between the distal edges 68 andthe side edges 147 of the rectangular composite structure 133. Theelastic material of the side panels 134 can be disposed in the interiorportions 78 to render the side panels elastomeric in a directiongenerally parallel to the transverse axis 49. Most desirably, each sidepanel 134 is elastomeric from a waist end edge 72 to a leg end edge 70.More specifically, individual samples of side panel material, takenbetween the waist end edge 72 and the leg end edge 70 parallel to thetransverse axis 49 and having a length from the attachment line 69 tothe distal edge 68 and a width of about 2 centimeters, are allelastomeric.

Suitable elastic materials, as well as one described process ofincorporating elastic side panels into a training pant, are described inthe following U.S. Pat. Nos. 4,940,464 issued Jul. 10, 1990 to VanGompel et al.; 5,224,405 issued Jul. 6, 1993 to Pohjola; 5,104,116issued Apr. 14, 1992 to Pohjola; and 5,046,272 issued Sep. 10, 1991 toVogt et al.; all of which are incorporated herein by reference. Inparticular embodiments, the elastic material includes a stretch-thermallaminate (STL), a neck-bonded laminate (NBL), a reversibly neckedlaminate, or a stretch-bonded laminate (SBL) material. Methods of makingsuch materials are well known to those skilled in the art and describedin U.S. Pat. No. 4,663,220 issued May 5, 1987 to Wisneski et al.; U.S.Pat. No. 5,226,992 issued Jul. 13, 1993 to Morman; and European PatentApplication No. EP 0 217 032 published on Apr. 8, 1987 in the names ofTaylor et al.; all of which are incorporated herein by reference.Alternatively, the side panel material may include other woven ornonwoven materials, such as those described above as being suitable forthe outer cover 44 or body side liner 42, or stretchable but inelasticmaterials.

The absorbent chassis 14 and the fastening system 80 together define arefastenable pant having a waist opening 13 and a pair of leg openings12 (FIG. 1). When the fastening system is engaged, it can be appreciatedthat the refastenable pant includes a pair of elastomeric front sidepanels 134 extending from the waist opening to each leg opening, a pairof elastomeric back side panels 234 extending from the waist opening toeach leg opening, a pair of refastenable seams 88 (FIG. 1) extendingfrom the waist opening to each leg opening and positioned between theelastomeric front and back side panels, an elastomeric front waistband154 positioned between the pair of elastomeric front side panels 134, anelastomeric back waistband 156 positioned between the pair ofelastomeric back side panels 234, and a pair of curved leg elastics 10which encircle each leg opening 12.

As described herein, the various components of the training pant 20 canbe integrally assembled together employing various types of suitableattachment means, such as adhesive, sonic and thermal bonds orcombinations thereof. The resulting product is an absorbent garment 20having a comfortable, gasket-like fit and an aesthetically pleasing,finished look about the leg openings 12. The gasket-like fit caneliminate a need for separately attached side flaps, thereby eliminatingadditional time and material costs. The pant-like absorbent garment 20can be sized and tailored for a wide variety of uses including, forexample, diapers, training pants, swimwear, adult incontinence garments,and the like. The curved leg elastics of the present invention can alsobe used for curved standing leg cuffs. Alternatively, leak guard flapscan be attached to an absorbent garment in the same manner as the legelastics are attached to an absorbent garment in the present invention.

It will be appreciated that details of the foregoing embodiments, givenfor purposes of illustration, are not to be construed as limiting thescope of this invention. Although only a few exemplary embodiments ofthis invention have been described in detail above, those skilled in theart will readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention, which is defined in the following claims and all equivalentsthereto. Further, it is recognized that many embodiments may beconceived that do not achieve all of the advantages of some embodiments,particularly of the preferred embodiments, yet the absence of aparticular advantage shall not be construed to necessarily mean thatsuch an embodiment is outside the scope of the present invention.

We claim:
 1. A method of producing curved leg elastics comprising thesteps of: guiding a pair of elastic ribbons onto a pair of complementarypucks, each puck having a first curved surface; directing each elasticribbon to follow a contour of the first curved surface of one of thepucks; severing each of the elastic ribbons into a discrete piece;moving the pucks toward a substrate; and bonding the pieces of theelastic ribbons to the substrate.
 2. The method of claim 1, wherein thestep of moving the pucks comprises rotating the pucks toward thesubstrate.
 3. The method of claim 2, wherein the pucks are oscillated byabout 90 degrees from a plane substantially perpendicular to thesubstrate.
 4. The method of claim 1, wherein the step of moving thepucks comprises rotating the pucks in a plane substantially parallel tothe substrate.
 5. The method of claim 4, wherein the step of moving thepucks further comprises oscillating the pucks from a plane substantiallyperpendicular to the substrate.
 6. The method of claim 1 wherein thepucks are attached to a rotating device.
 7. The method of claim 6,further comprising the step of adjusting the rotating device to changemachine direction spacing of the pucks.
 8. The method of claim 1,wherein each of the pucks further comprises a second curved surfaceadjacent the first curved surface.
 9. The method of claim 8 wherein thefirst curved surfaces of the pucks each at least partially comprise anonslip texture.
 10. The method of claim 8, further comprising the stepof directing a portion of each elastic ribbon onto the second curvedsurface of one of the pucks as the elastic ribbon is directed to followthe contour of the first curved side of the puck.
 11. The method ofclaim 10, wherein the portion of each of the pieces of the elasticribbons on the second curved surface of the puck is bonded to thesubstrate.
 12. The method of claim 1, further comprising the step ofapplying a vacuum to hold the elastic ribbons onto the pucks.
 13. Themethod of claim 1, wherein the bonding step comprises applying anadhesive to at least one of the elastic ribbons and the substrate. 14.The method of claim 1 wherein the bonding step comprises ultrasonicallybonding the pieces of elastic ribbon to the substrate.
 15. The method ofclaim 1 wherein the substrate comprises a stretchable material.
 16. Themethod of claim 1 wherein the substrate comprises curved cut-outs alongtwo parallel edges.
 17. A method of attaching leg elastics to asubstrate comprising the steps of: guiding a pair of elastic ribbonsonto a pair of opposing pucks, each puck having a first curved surfaceand a second surface adjacent the first curved surface; stretching anddisplacing each of the elastic ribbons so that the elastic ribbons eachfollow a contour of the curved surface of one of the pucks and a portionof each elastic ribbon is folded onto the second surface of the puck;severing each of the elastic ribbons into a discrete piece; rotating thepucks toward the substrate; and bonding the second surface portion ofeach of the pieces of the elastic ribbons to a curved edge of thesubstrate.
 18. The method of claim 17 wherein the pucks are attached toa rotating device.
 19. The method of claim 17, wherein the pucks arerotated in a plane that is substantially parallel to the substrate. 20.The method of claim 17, wherein the pucks are oscillated from a planethat is substantially perpendicular to the substrate.
 21. The method ofclaim 17 wherein the pair of pucks is aligned during bonding such thatthe first curved surfaces of the pucks face each other.
 22. The methodof claim 17, further comprising the step of applying a vacuum to holdthe elastic ribbons on the pucks.
 23. The method of claim 17 wherein thefirst curved surfaces of the pucks each at least partially comprise anonslip texture.
 24. The method of claim 17, farther comprising the stepof applying an adhesive to at least one of the elastic ribbons and thesubstrate, to bond the second surface portion of each of the elasticribbons to the substrate.
 25. The method of claim 17 wherein the bondingstep comprises ultrasonically bonding the pieces of elastic ribbon tothe substrate.
 26. The method of claim 17 wherein the substratecomprises a stretchable material.
 27. A method of attaching leg elasticsto a substrate comprising the steps of: guiding a pair of continuouselastic ribbons onto a pair of pucks; placing each elastic ribbon sothat the elastic ribbon follows a contour of a first curved surface ofone of the pucks and a portion of the elastic ribbon is folded over anedge of the puck onto a second surface of the puck; severing the elasticribbons into discrete pieces; rotating the pucks toward the substrate;and bonding the second surface portion of each piece of the elasticribbon to the substrate.
 28. The method of claim 27, wherein the pucksare oscillated by about 45 to about 135 degrees in a plane substantiallyperpendicular to the substrate.
 29. The method of claim 27 wherein eachof the pucks is attached to a rotating device which rotates in adirection substantially parallel to the substrate.